K=95.8 circular mil ohms per foot. It is the resistance of a conductor 0.001 inch in diameter one foot long at 20 degrees C in this case. L=1640 is one way circuit length in feet CMA=16512 is the circular mil area of the No. 8 steel wire that is the diameter in thousandths of an inch squared I is amperes VD is voltage drop VD=2KLI/CMA is a standard formual for finding voltage drop for 60 hertz single phase or Direct Current This is the standard formula used by electricians to find voltage drop for the last 50 years or so.. We multiply VD by 0.866 for three phase three wire and by 0.5 for three phase four wire If you use 24 volts the NEC rules apply and bare conductors cannot be used, but by using the electric fence model the NEC rules do not apply.
-------------------- Thanks for the definition of terms. I have not used the "standard formula" and generally use metric so I simply go back to basics: Resistance =resistivity*length/area for conductors and the rest follows. This is, as I suspected, part of the basis for your standard formula but I wanted to be sure as I suspect any "formula" until I see the basis for it. The remaining part consists of assumptions of unity pf and negligable inductance- both reasonable in commercial and domestic applications as well as some industrial applications. They are reasonable in this case as well-given negligable transformer impedances (and exciting currents) which may not be the case.
However the reason for your proposal is to get around NEC rules Fair enough. It is a situation that code doesn't cover or prohibits (whether, in a specific case such as this, the code is an ass is another matter ).
Basically, a 24V scheme will work. Will it violate code? Yes. Will it work better than a HV system- I think so. Will it be safer? Maybe, maybe not- but it can be, in spite of the code.